Vapor arcing electric converting device



- O. K. MARTI VAPOR ARCING ELECTRIC CONVERTING DEVICE Nov. 11, 1941 Filed April 29, 1940 2 Sheets-Sheet 1 mm km m lJ/I/ll' V//////////////////l7 .r///// L mm Wm km QM Q H HH HU H QM V 8 A m N\ Q0, EN N\\ Q v. wm R, a mm w m 5 H mm x m. w \m A wh wu 0N Vm NOV. 11, 1941. MARTI' 2,262,189

VAPOR ARCING ELECTRIC CONVERTING DEVICE Filed April 29, 1940 2 Sheets-Sheet 2 Patented Nov. 11, 1941 VAPOR ARCING ELECTRIC CONVERTING DEVICE Othmar K. Marti, Wauwatosa, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application April 29, 1940, Serial No. 332,144

18 Claims.

The present invention relates to improvements in vapor arcing electric current converting devices and more particularly to such converting devices of the multi-anode liquid cathode vapor arcing type.

In conventional multi-anode liquid cathode electric current converting devices heretofore utilized the anodes are usually encompassed by metallic shields, or arc guides, and arranged in a circle about a liquid cathode of relatively small continuous arcing area positioned about the center of the bottom wall of a substantially gas tight highly evacuated enclosing envelope. In such construction, with adequate electrical and mechanical clearances together with other minimum restrictions, the anodes are necessarily so positioned relative to the arcing surface of the cathode that are voltage drops between the terminals of the anodes and cathode range from a minimum of approximately twenty volts at very light current loads to approximately thirty volts at heavy current loads. The efficiencies of converters of such construction are not, therefore, such as to render them generally acceptable for the conversion of currents at output voltages materially below five hundred volts.

A further undesirable feature of electric current converters of the foregoing construction resides in the difilculties experienced in maintaining a suitable vacuum within the arc paths by reason of leakage thereinto of air or other gases, particularly hydrogen, through the seals and casing walls, it being well known that deterioration of the vacuum tends to cause destructive reverse flow of current through the device and to cause the insulation materials between the different elements of the device to become coated with films of electrically conductive material.

It is, therefore, an object of the present invention to provide an electric current converting device of the multi-anode liquid cathode vapor arcing typewhich shall be capable of converting electric currents of many hundreds of amperes per anode with an arc drop voltage of materially less than twenty volts between the terminals of the anodes and the cathode thereof.

Another object of the present invention is to provide an electric current converting device of the multi-anode liquid cathode vapor arcing type in which the anodes are positioned within a substantially gas tight highly evacuated chamber and in which the arcing surfaces thereof severally face the arcing surfaces of different associated segregated electrically connected portions of the cathode.

Another object of the present invention is the provision in an electric current converter of the multi-anode liquid cathode vapor arcing type of means for evacuating a plurality of arcing chambers enclosed within a substantially gas tight chamber and means for separately evacuating the latter chamber to thereby prevent the leakage of gases therefrom into the arcing chambers.

Another object of the present invention is the provision of an electric current converter having a plurality of arcing chambers, each comprising an anode enclosed within a metallic shield, removably supported within a substantially gas tight highly evacuated chamber and each of which arcing chambers is operatively associated with a different one of a plurality of segregated connected portions of a liquid cathode.

Other objects and structural details of the invention will be apparent from the following description and claims when read in connection with the'accompanying drawings wherein similar parts are indicated by the same characters of reference throughout all figures of the drawmgs:

Fig. 1 is a vertical sectional view of a portion of a multi-anode electric current converter showing one of a plurality of arcing chambers and a portion of an enclosing gas tight chamber, and including one of a plurality of segregated portions of the cathode;

Fig. 2 is a plan view of the converter illustrated in Fig. 1 showing one mounting arrangement of six arcing chambers enclosed within an enveloping gas tight chamber and indicating one arrangement for separately evacuating the arcing chambers and the enveloping chamber;

Fig. 3 is a vertical view partly in section, along thepiane IV-IV of Fig. 2, showing two of the arcing chambers in elevation;

Fig. 4 is a sectional view similar to Fig. 1 but showing a modified arrangement of the arcing chambers and the means for supporting the same on the top wall of the enveloping gas tight chamber;

Fig. 5 is a sectional view showing details of the ignition anode assembly of Fig. 4; and Fig. 6 is a sectional view showing details of the excitation anode assembly of Fig. 4.

Referring to the embodiment of the invention as illustrated in Figs. 1, 2 and 3 of the drawings by characters of reference, the reference numeral I0 designates a hermetically closed highly evacuated chamber having an oblong side wall portion II, a bottom wall portion l2 and a top wall portion l3 constructed of suitable metallic materia1such as rolled steeland supported on a plurality of suitably positioned insulators Id. As indicated in Figs. 1 and 3 of the drawings, the side wall ll includes an outwardly extending annular fiange l5 welded or otherwise suitably aflixed thereto and a downwardly extending cone shaped portion I6 which may be formed integral with the bottom wall i2. The bottom wall 12 defines a plurality of cups or wells ii having substantially fiat bottom walls and relatively short upstanding cylindrical side walls constituting receptacles for a plurality of pools of mercury, or its equivalent, l8 severally serving as segregated electrically connected portions of a liquid cathode and constituting sources of ionizable vapor. The wells I! are interconnected by pipes i9 forming passages for the flow of cathode material therebetween, and include rings of quartz or other suitable heat resistant insulating material, immersed in the cathode material for confining the active portions thereof within the limits of the rings to thereby prevent excessive heating of the side walls of the wells IT. The top wall I3 is removably afiixed in gas tight relation to the side wall H by means including an annular gasket 2| of rubber or other suitable resilient material and compressed against the flange l5 by suitable means such as bolts 22 disposed circumferentially along the flange l5 and passing through apertures in the wall 13 and the flange I5.

As more clearly shown in Fig. 1 of the drawings, the top wall I3 has a plurality of apertures through which project anodes 23 severally enclosed within chambers 2 5 having apertured top walls 25 and side walls 26 of rolled steel, or other suitable material, removably affixed to the wall l3 as by compressing annular gaskets 2'? of rubber, or other suitable resilient material, between the walls Zii and i3 by means such as bolts 28 disposed circumferentially along the walls 25 and passing through insulating bushings 29 extending through apertures in the walls 25 and screwed into the wall E3 to form gas tight insulated joints between the walls 25 and wall it. The inner, bottom and lower outer surfaces of the walls 26 include a coating of insulating material 38 such, for example, as a vitreous enamel. The walls 26 are welded or otherwise suitably afiixed at their upper ends to the lower surface of the walls 25 and (as illustrated in Fig. 1 of the drawings), immersed at their lower ends in the segregated portions 58 of the cathode intermediate the side walls thereof and the ring insulators 20 to thereby form a plurality of substantially gas tight arcing chambers 2 3. If desired, however, the bottom ends of the walls 26 may terminate above the surface of the associated portions of the cathode, as shown in the embodiment according to Fig. 4 of the drawings hereinafter described.

The anodes 23 comprise massive head portions of heat resistant material of high thermal emissivity, such, for example, as graphite, with arcing surfaces 3| facing the arcing surfaces of the associated ones of the segregated portions l8 of the cathode and with side wall surfaces 32 extending coaxially to the side walls 26. The head portions of the anodes are shown as being screwed to the stem, or lead in conductor, portions 33 of rolled steel or other suitable material, extending through and fixedly attached to annular insulators of any suitable construction, such, for example, as a plurality of superposed vitreous enamel coated sealed together metallic rings 35 welded or otherwise suitably affixed in gas tight relation to the lead in conductors 33 and to the walls 25.

In order that stable operation may be secured at a voltage drop of materially less than twenty volts between the terminals of the anodes and the associated segregated portions of the cathode, the arcing surfaces of the anodes should be positioned within a range of from approximately ten inches to approximately thirteen inches from the arcing surface of the associated portions of the cathode. Repeated tests have demonstrated that during periods of heavy current loads, backfires (reverse flows of current) occurred when the arcing surfaces of the anodes were positioned at distances less than approximately ten inches from the arcing surfaces of the cathode; and that a very material increase in the voltage drop between the terminals of the anodes and the cathode occurred when such surfaces were positioned at distances greater than approximately thirteen inchcs, as occurs in the conventional multi-anode single cathode converter by reason of greater distances between the anodes and cathode and by reason of necessary restrictions such as curvatures or bends in the arc paths.

Although any one of numerous well known means may be employed which will permit continual initiation of arcs for the flow of current between the anodes 23 and the associated portions i8 of the cathode, the arrangement shown in detail in the drawings may preferably be utilized. This arrangement comprises the continuous vaporization and ionization of material of the respective segregated portions of the cathode by way of arcs between auxiliary electrodes, usually referred to as excitation anodes, and the associated portions of the cathode. The arcs between the excitation anodes and the associated portions of the cathode may be initiated by any of the numerous well known means for initiating vaporization and ionization of material of the respective segregated portions of the cathode and as illustrated in Fig. l of the drawings comprises ignition anodes 35 severally affixed to the walls 26 with the arcing surfaces thereof positioned substantially one inch from the arcing surfaces of the associated segregated portions of the cathode. The anodes 35 may be supported in either electrically conductive or in insulated relation to the walls 26 as preferred. Cooperating with the anodes 35 are solenoids 36 severally arranged about extensions 31 on the bottom walls of the wells ii. The extensions 31 are made of magnetic material and constitute the fixed cores of the solenoids. Each of the extensions includes a hollowed portion defining a cylinder for accommodating a movable armature 38. The armatures 38 are severally preferably so shaped as to engage the wall surfaces of the cylinders in substantially liquid tight relation therewith and may preferably be provided with a coating of suitable non-magnetic material for preventing excessive magnetic attraction between the armatures and the walls of the cylinders The armatures 88 are severally drilled to form nozzles directed towards the associated ones of the ignition anodes 35 and are adapted to produce momentarily jets of cathode material extending through the associated segregated portions of the cathode and between such cathode portions and the associated ones of the anodes 35 upon the downward movements of the armatures 38 against the action of springs 39 from the rest position shown, responsive to energizations of the solenoids 36. The source of current (not shown) for energizing the solenoids 36 may be either alternating or direct current as preferred, or as conditions may direct, and the same holds true with respect to the establishments of the arcs between the ignition anodes 35 and the associated segregated portions l8 of the cathode. In cases where the anodes 35 are arranged in electrically conductive connection with the casing walls 26 resistors 40 enclosed in insulators 4| should be included in the connections of such anodes 35 with'the walls 26.

As indicated more clearly in Fig. 1 of the drawings, at least one aperture extends through each of the walls 26 intermediate the associated anode 23 and the segregated portion l6 of the cathode,

to which is affixed in gas tight. relation, as by welding, a tubulated outwardly extending arm 42 of suitable material, such as rolled steel, through which extends, in electrically insulated gas tight relation thereto, an auxiliary electrode generally referred to as an excitation anode, operative from a suitable source of current (not shown) through a lead in conductor 52 extending through the wall in electrically insulated gas tight relation thereto, to continuously vaporize and ionize material of the associated segregated portion of the cathode, to thereby continuously provide a medium for the continual initiation of arcs for the fiow of current between the associated anode 23 and segregated portion ll! of the cathode.

In cases where it is desired to excite the arcing chambers from a source of direct current a single excitation anode 5| only per arcing chamber will suflice, but in cases where it is desired to excite the chambers from a source of alternating cur-' rent two alternately operative excitation anodes 5| per arcing chamber will be required and preferably positioned on opposite sides of the associated ignition anode at. points substantially ninety degrees on the periphery of the walls'26; and tests have demonstrated that the most stable operation of such electrodes is secured by tilting the same in a direction towards the associated segregated portions I8 of the cathode with the center of the arcing surfaces of the excitation anodes substantially four inches from the arcing surfaces of the associated cathode portions.

Moreover, the head portions of the excitation anodes 5| should preferably extend slightly inward from the walls 26 and be encompassed by tubular shields 53 of either electrically conductive or insulating heat resistant material in spaced relation thereto and in spaced relation to the walls forming the apertures. The shields 53 should extend a short distance beyond the arcing surfaces of the anodes 5| and they function to shield the arcing surfaces thereof from direct blasts of vapor and globules of material emitted from the cathode portions l8, and to prevent undue cooling of the excitation anodes by reason of the proximity thereof to the cooled walls 26.

In order that the moments of the recurring initiation of the flow of current between the respective anodes 23 and the associated ones of the segregated portions l8 of the cathode may be regulated, and in order that liquid particles of the cathode material may be prevented from impinging 0n the arcing surfaces 3| of the anodes 23 to such an extent as would result in the creation of cathode spots thereon, and consequent initiation of backfires, i. e., reverse flows of current from the cathode to the anodes, a control electrode 54 (also called grid) having a plurality of apertures therein is positioned across each of the arcing chambers 24 intermediate the associated segregated portion |8 of the cathode and the anode 23 thereof. In order that such control electrodes may satisfactorily perform their required functions, it'is essential, as demonstrated by repeated tests, that they be positioned across the paths for the flow of vapor from the segregated portions 8 of the cathode within a predetermined range of distances from the anodes 23 and that their dimensions as to thickness and area of the respective apertures therethrough be also within predetermined ranges.

Accordingly, control electrodes 54 of suitable heat resistant electrically conductive material, such as graphite, having a thickness of substantially one-half inch and a large number of substantially equally spaced circular apertures 55 each of substantially one-half inch diameter are severally suspended across the arcing chambers 24 with their upper surfaces positioned substantially one inch below the arcing surfaces 3| of the anodes 23. As clearly shown in Fig. 1 of the drawings, the control electrodes 54 are fixedly supported in position by attachment to the lower ends of tubes 56 of any suitable material, encompassing the anodes 23 and screwed, or otherwise suitably aflixed, to the anode guide insulators 51 embedded in the walls 25. Although subject to some variation, the inner walls of the tubes 56 should, preferably, be spaced substantially one inch from the side Wall surfaces 32 of the anodes 23.

For the purpose of impressing potentials from external sources of current (not shown) on the control electrodes 54 of such characteristics as will control the moments of the initiation of. and prevent the establishment of arcs for the flow of current between the respective anodes 23 and the associated segregated portions N3 of the cathode, electrically conductive connections are severally led from the control electrodes 54, by

way of the tubes 56, through suitably insulated lead in conductors 58 extending through apertures in the walls 25. The conductors 58 are supported in gas tight relation to the walls 25 as by being embedded in annular insulators 59 supported by packing rings 60 of rubber, or other suitable resilient material, compressed against the insulators 59 and the walls of the apertures through walls 25.

As shown in Figs. 1 and 3 of the drawings, the outer surfaces of the side walls 26 of the respective arcing chambers 24 have coiled thereabout pipes 6| of steel, or other suitable material of high heat conductivity, with inlet and outlet portions extending through walls 25 in gas tight relation thereto. The pipes 6| are preferably welded to the walls 26 and form passages for the flow therethrough of a cooling fluid (not shown), such as water, to thereby regulate the density of the vapor generated from the respective segregated portions |8 of the cathode and to maintain the various elements of the converter within predetermined ranges of temperatures. It will be understood, however, that cooling means other than the pipes as shown may be employed for controlling the rate of condensation of the vapors and for controlling the temperatures of the elements of the converter.

As shown in Fig. 1 of the drawings, each of the walls 25 is provided with an aperture to which is connected in gas tight relation a conuation from the arcing chambers 241 of such foreign gases as may be liberated, from time to time, from the walls of the arcing chambers and from the elements of the converter contained therein. As indicated in Fig. 2 of the drawings, the conduits H are severally connected through insulated joints i2 therein with a common header 73. The header '13 is. in turn, connected through an additional conduit I 5, having an insulated joint 15 interposed therein, to a common pumping unit comprising a static socalled high vacuum mercury vapor pump 16, and a serially connected rotary vacuum pump ll. The wall I 3 is similarly provided with an aperture connected in a gas tight manner through an additional conduit 79, having an insulated joint 80 interposed therein, to an additional pumping unit 16, I1 for the independent evacuation of gases from the chamber Ill. Instead of employing two independent operating pumping units as shown, the two high vacuum static pumps may, if desired, be connected with and exhausted through a single rotary pump ll. Or, as a further simplification, the conduit 79 of suitable size and length relative to the size and lengths of the conduits ll may be connected with the common header 13 and all of the chambers 2t and iii, exhausted through a single pumping unit it, H. The exhaustion of the chamber ID by means independent of the means for exhausting the chambers 26 is, however, preferable as thereby the chamber l may mor readily be maintained at such pressures relative to the pressures within the arcing chambers 24!, as to more readily facilitate preventing such gases as may leak into the chamber ID from entering into the arcing chambers 28.

The pressure difference effected by the high vacuum mercury pumps 18 from their inlets receiving fluid from conduits 78, F9, to their outlets discharging to conduits 760 is of the order of one thousand microns and the pressure difference effected by the rotary pumps ill from their inlets receiving fiuid from conduits 780, to their final discharge fiues Till, is of the order of seven hundred and fifty-nine thousand microns. The pressure differences indicated are on the assumption that the atmospheric pressure is seven hundred and sixty thousand microns. Although not illustrated in the drawings, it will be readily understood by those skilled in the art that in the practice of the invention the usual pressure measuring devices will be included in the connections of the chambers 86, 28 to the pumps 76, 77, and that such devices include connections controlling the operation of the pumps in dependence upon the pressures within the chambers i0, 2 3. Although subject to some variation, the measuring devices should preferably be so calibrated and connected as to cause the pumps to maintain the gas pressures within the arcing chambers 2% at not to exceed approximately two to three microns and the gas pressure within the chamber H3 at not to exceed approximately one micron when measured on the McLeod gauge during operation of the converter within its rated normal capacity; and, by reason of the continuous vaporization of the cathode material, the combined gas and vapor pressure within the arcing chambers 2 will vary from one hundred to three hundred microns depending upon (a) the load conditions within the rated normal capacity of the converter, (b) the position of the pressure measuring device employed relative to the arcing surfaces of the segregated portions of the cathode, and (0) whether the arcing chambers 26 be gas tight as shown in Fig. l or include passages, as shown in Fig. 4, for the flow of vapor therefrom to the chamber iii. Thus during operation of the converter within its rated normal capacity the pressure within the chamber it) may be maintained at approximately one hundred to three hundred microns below the pressure within the chambers 2 3.

In the embodiment according to Fig, 4 of the drawings, the elements of the arcing chambers are supported directly on the top wall l3 of the chamber In. In this embodiment the side walls M of the arcing chambers are supported in insulated relation to both the segregated portions of the cathode and the casing defining the chamber ID, as by terminating the bottom ends of the walls 8| at a point above the upper surface of the segregated cathode portions I8 intermediate the rings 20 and the side walls of the wells ll, and supporting the same on the wall l3 through the interposition of annular insulators 82 clamped between guide rings 83 and rings 8 3 of rolled steel, or other suitable material, welded or otherwise suitably affixed to the lower surface of the wall 83, by means of bolts 85 extending through apertures in suitably positioned outwardly extending lugs 86, 87, of rolled steel, or other suitable material, welded or otherwise suitably afiixed to the walls ill and rings M, respectively. As shown in the drawings, the bolts 95 are supported in insulated relation to the lugs 86 by means comprising annular insulators 8B of porcelain, or other suitable heat resistant insulating material, extending through apertures in the lugs 86. Compression springs 89 interposed between the lugs 8'! and nuts 90 operate to maintain the walls ill and insulators 82 in clamped engagement with rings 86 and to compensate for any diiferences in expansion and contraction of walls 8! and insulators 82 by reason of variations in temperature to which these parts are subjected during operation of the converter. It will be understood, however, that the walls Bl may be coated with an insulating material and immersed at their lower ends in the associated portions of the cathode as shown and described with respect to the embodiment according to Fig. l. of the drawings.

Instead of supporting the anodes 23 and the grid supporting tubes 56 on guide insulators 57, as in fig. l, the anodes 23 and tubes 58 of the embodiment of Fig. 4 may be supported on serrated annular insulators 9i clamped between the upper surfaces of the head portions of the anodes 23 and the wall it, as by screwing the head portions to the lead in conductors 33 thereof. Annular gaskets 92 of suitable resilient heat resistant material, such as asbestos, may preferably be interposed between the insulators 9i and the wall it.

Upstanding cylindrical members 93, of suitable heat resistant material such as quartz, are severally immersed in the segregated portions of the cathode, in spaced coaxial relation to the rings 2@, to thereby confine therein the active surfaces of the segregated portions of the cathode.

Each of the members 93 has an aperture through which extends the ignition anode which, as shown in detail in Fig. 5 of the drawings, comprises a head portion 9 8 of graphite, or other suitable heat resistant conductive material,

ceeds eight hundred amperes an additional bafllescrewed or otherwise suitably affixed to a stem portion 95 of steel, or other suitable material. The stem portions 95 are, in turn, severally afiixed to lead in conductors 96 of steel, or other suitable material, which extend through the wall I3 in gas tight insulated relation thereto by suitable means (not shown). All portions of the ignition anodes, other than the arcing surfaces thereof, and the lead in conductors 96 are encased within insulators 91, 98, 99, of quartz or other suitable aterial.

The members 93 are provided with additional apertures forming passages for the flow of the sustaining arcs between the excitation anodes and the segregated portions of the cathodes. As shown in detail in Fig. 6 of the drawings, the excitation anodes of this embodiment of the invention comprise cup shaped head portions I II) of graphite or other suitable heat resistant electrically conductive material, severally screwed into stem portions III, which are, in turn, screwed into or otherwise suitably affixed to lead in conductors H2. The stem portions II I and lead in conductors H2 may be of steel and are encased in insulators H3 and H4 of quartz or other suitable heat resistant material. head portions H of the excitation anodes are severally encompassed by spaced apart tubular shields H5 and H6 of any suitable insulating or electrically conductive heat resistant material and retained in position by screwing the shield H5 onto the insulator H3, to thereby maintain the density of the vapor and temperature at the arcing surfaces of the anode head portions H0 within desired limits. Instead of extending the excitation anodes, III], III through the side walls 8| of the arcing chambers, as in the embodiment of the invention according to Fig. 1 of the drawings, they are retained wholly within the arcing chambers and their lead in conductors The H2 extend through apertures in wall I3 in gas tight insulated relation thereto by means comprising annular gaskets II8 of rubber or other suitable insulating material, compressed in gas tight relation to the walls defining the apertures and the lead in conductors H2 by annular insulators H9 supported on shoulders I20 of the apertures and annular insulators I2I pressed against the gaskets H8 by metallic clamping bushings I22.

Each of the side walls 8| has coiled thereabout, in spaced relation thereto, one or more pipes I23 extending through the wall I3 in gas tight relation thereto forming passages for the flow of cooling fluid (not shown), such as water, therethrough to thereby regulate the density of the vapor'generated from the segregated portions I8 of the cathode and to maintain the elements of the converter within predetermined ranges of temperature. It will be understood, however, that the pipes I23 may be coiled in physical contact with the walls BI and that in such case it will be necessary that .the passage thereof through the wall I3 shall be in insulated as well as gas tight relation thereto.

In cases when the flow of current through the converter exceeds four hundred amperes per anode, a second control electrode, similar to the control electrode 54, should be suspended across each of the arcing chambers intermediate the control electrodes 54 and the associated segregated portions of the cathode with the upper surfaces thereof substantially one inch below the lower surfaces of the control electrodes 54; and in cases when the flow of current per anode exshould be interposed between each of the segregated portions of the cathode and the lower one of the two control electrodes of such dimensions as to intercept and deflect the vapor and liquid particles of the cathode material towards the cooled side walls of the arcing chambers.

Although but two embodiments of the present invention have been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims. Some of the features of the invention disclosed herein are claimed in a copending application of Othmar K. Marti, Serial No. 310,980, filed December 26, 1939.

It is claimed and desired to secure by Letters Patent:

1. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber, a liquid cathode supported within said chamber, an anode associated with said cathode and depending into said chamber, a wall encompassing said anode and defining with said cathode a separate'chamber within the first'said chamber, means for initiating vaporization and ionization of portions of said cathode to thereby form a medium for the flow of current between said anode and cathode, means for evacuating the said separate chamber, and means separated from the first said evacuating means for evacuating and for maintaining said gas tight chamber at a pressure lower than the pressure within the said separate chamber.

2. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber, a liquid cathode supported within said chamber, an anode associated with said cathode and depending into said chamber, a wall encompassing said anode and defining with said cathode a second substantially gas tight chamber within the first said chamber, means for initiating vaporization and ionization of portons of said cathode to thereby form a medium for the fiow of current between said anode and cathode, and means for evacuating each of said chambers including means for manitaining the first said chamber at a pressure lower than the pressure within the said second chamber.

3. In an electric current converter of the vapor arcing type, a casing defining-a substantially gas tight chamber, a liquid cathode divided into a plurality of segregated portions supported within said chamber, a plurality of anodes severally associated with said cathode portions and depending into said chamber, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate chambers, means for initiating vaporization and ionization of material of each of said portions of said cathode to thereby form mediums for the flow of current between said anodes and the associated portions of said cathode, means for evacuating each of the said separate chambers, and separate means for evacuating and for maintaining the first said chamber at a pressure lower than the pressure within each of said separate chambers.

4. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of electrically connected segregated portions severally supported within said cups, a plurality of anodes severally associated with said cathode portions and depending into said chamber, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate chambers, means for initiating vaporization and ionization of material of each of the portions of said cathode to thereby form a medium for the fiow of current between said anodes and the associated portions of said cathode, means for evacuating each of said separate chambers, and separate means for evacuating and for maintaining the first said chamber at a pressure lower than the pressure within each of the said separate chambers.

5. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber having a bottom wall forming cups, :3. liquid cathode divided into a plurality of segregated portions severally supported within said cups, a plurality of anodes severally associated with said cathode portions depending into said chamber, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode a plurality of separate substantially gas tight chambers within the first said chamber, means for initiating vaporization and ionization of material of each of said portions of said cathode to thereby form a medium for the flow of current between said anodes and the associated portions of said cathode, and means for evacuating each of said chambers including means for maintaining the first said chamber at a pressure lower than the pressure within each of the said separate chambers.

6. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber, a liquid cathode divided into a plurality of segregated portions supported within said chamber, a plurality of anodes severally associated with said cathode portions depending into said chamber, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate substantially gas tight chambers within the first said chamber, means for initiating vaporization and ionization of material of each of said portions of said cathode to thereby form a medium for the fiow of current between said anodes and the associated portions of said cathode, a header common to said chambers, and means for simultaneously evacuating said chambers through said header including means for maintaining the first said chamber at a pressure lower than the pressure within each of the said separate chambers.

7. In an electric current converter of the vapor arcing type, a casing defining a substantially gas tight chamber, a liquid cathode divided into a plurality of segregated portions supported within said chamber, a plurality of anodes depending into said chamber having arcing surfaces severally facing said cathode portions, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate substantially gas tight chambers within the first said chamber, means for initiating and continuously vaporizing and for continuously ionizing material of each of said portions of said cathode to thereby form a medium for the fiow of current between said anodes and the associated portions of said cathode, means for controlling the density of said vaporized portions comprising means forming a passage for the fiow of a cooling medium in heat transfer aecaiea l relation to said walls, and means for simultaneously evacuating each of said chambers including means for maintaining the first said chamber at a pressure lower than the pressure within each of the said separate chambers.

8. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of segregated portions severally supported within said cups, a plurality of anodes depending into said chamber having arcing surfaces severally facing said cathode portions, a plurality of walls severally encompassing said anodes and forming with the associated portions of said cathode separate substantially gas tight chambers within the first said chamber, means for initiating vaporization and ionization of material of each of said portions of said cathode to thereby form a medium for the fiow of current between said anodes and the associated portions of said cathode, means for simultaneously evacuating said chambers comprising a header common to said chambers, a plurality of conduits severally connecting said chambers to said header, a plurality of insulated joints severally included in the connections of said conduits to said header, and means for controlling the density of said vapor within said chambers comprising means forming passages for the fiow of a cooling medium in heat transfer relation to said walls.

9. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of segregated portions severally supported within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions, a plurality of walls of electrically conductive material severally encompassing said anodes in electrically insulated relation thereto and forming, with the associated portions of said cathode and top wall portions of said casing, a plurality of separate chambers within the first said chamber, means comprising a plurality of auxiliary electrodes severally associated with said cathode portions for continuously vaporizing and for continuously ionizing material thereof to form a medium for the continual flow of current between the respective said anodes and the associated portions of said cathode, means for simultaneously evacuating said chambers comprising a header common to said chambers, a plurality of conduits severally connecting said chambers to said header, a plurality of insulated joints severally included in the connections of said conduits to said header, and means for controlling the density of said vapor within said chambers comprising means forming passages for the flow of a cooling medium in heat transfer relation to said walls.

10. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber, a liquid cathode divided into a plurality of segregated electrically connected portions supported within said chamber, a plurality of anodes severally associated with said cathode portions depending into said chamber in insulated relation to the walls thereof, a plurality of walls severally encompassing said anodes and forming with the associated portions of said cathode separate chambers within the first said chamber, means severally associated with said cathode portions for initiating vaporization and ionization of said cathode portions, means severally associated with said cathode portions for continuously vaporizing and for continuously ionizing material thereof to form a medium for the flow of current between said anodes and the associated portions of said cathode, and means for evacuating said chambers.

11. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups. a liquid cathode divided into a plurality of segregated electrically connected portions severally supported within said cups, a plurality oi anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces facing said cathode portions, a plurality of -walls severally encompassing said anodes and forming with the associated portions of said cathode separate chambers within the first said chamber, means severally associated with said cathode portions for initiating vaporization and ionization of material thereof, means severally associated with said cathode portions for continuously vaporizing and for continuously ionizing material thereof to form a medium for the flow of current between said anodes and the associated portions of said cathode, means for controlling the moments of initiation of said flow of current comprising aplurality of control electrodes severally associated with said anodes, means for controlling the density of the vapor within said separate chambers comprising means forming passages for the fiow of a cooling fluid in heat transfer relation to the walls of said separate chambers, and means for evacuating said chambers.

12. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of segregated electrically connected portions severally disposed within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions and spaced therefrom at a predetermined fixed distance to provide a total potential drop of materially less than twenty volts between the terminals of said anodes and the associated portions of said cathode during periods of the conduction of a current of substantially four hundred amperes by way of arcs therebetween, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate chambers within the first said chamber, means severally associated with said portions of said cathode to continuously vaporize and to continuously ionize material thereof, and means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fiuid in heat transfer relation to said walls.

13. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a wall forming cups, a liquid cathode divided into a plurality of segregated electrically connected portions severally supported within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions and spaced therefrom at a predetermined fixed distance to provide a total potential drop of materially less than twenty volts between the terminals of said anodes and the associated portions of said cathode during periods of the conduction of a current of substantially four hundred amperes by way of arcs therebetween, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate substantially gas tight chambers within the first said chamber, means severally associated with said portions of said cathode to continuously vaporize and to continuously ionize material thereof, means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fluid in heat transfer relation to said walls, and means severally operable to evacuate said chambers.

14. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of segregated electrically connected portions severally supported within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions and spaced therefrom at a predetermined fixed distance to provide a total potential drop of materially less than twenty volts between the terminals of said anodes and the associated portions of said cathode during periods of the conduction of a current of substantially four hundred amperes by way of arcs therebetween, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate-substantially gas tight chambers within the first said chamber, means severally associated with said portions of said cathode to continuously vaporize and ionize material thereof, means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fiuid in heat transfer relation to said walls, means operable to evacuate the said separate chambers, and means independently operable to evacuate the first said chamber to a pressure lower than the pressures within each of the said separate chambers.

15. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, 2. liquid cathode divided into a plurality of segregated electrically connected portions severally disposed within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions and spaced therefrom at a predetermined distance to provide a potential drop of materially less than twenty volts between the terminals of said anodes and the associated portions of said I cathode during periods of the conduction of a current of substantially four hundred amperes by way of arcs therebetween, a plurality of walls severally encompassing said anodes and defining with the associated portions of said cathode separate chambers within the first said chamber,

means severally associated with said portions of said cathode to continuously vaporize and to continuously ionize material thereof, means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fluid in heat transfer relation to said walls, means for controlling the moments of the continual initiation of the flow of current between said anodes and said cathode portions comprising a plurality of control electrodes severally posi tioned intermediate the arcing surfaces of said anodes and the associated ones of the segregated and having the bottom ends thereof severally iniportions of said cathode and having supporting members encompassing said anodes at a distance substantially one inch from the surface thereof.

16. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber, a liquid cathode divided into a plurality of segregated portions severally supported within said chamber, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions, a plurality of walls of electrically conductive material severally encompassing said anodes in insulated relation thereto, the said walls being supported in insulated relation to said cathode portions and the walls forming said casing and forming therewith a plurality of separate substantially gas tight chambers within the first said chamber, means for initiating vaporization and ionization of material of each of said portions of said cathode, and means for evacuating each of said chambers.

17. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall formi cups, a liquid cathode divided into a plurality of segregated electrically connected portions severally supported within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions, a plurality of walls of electrically conductive material supported on the top wall of said casing in insulated relation thereto severally encompassing said anodes in insulated relation thereto mersed within the said cathode portions in insulated relation thereto and defining therewith a plurality of separate substantially gas tight chambers within the first said chamber, means severally associated with said cathode portions to continuously vaporize and to continuously ionize material thereof to form a medium for the flow of current between said anodes and the associated portions of said cathode by way of arcs therebetween, means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fluid in heat transfer relation to said walls, and means severally operable to evacuate said chambers.

18. In an electric current converter of the vapor arcing type, a casing of electrically conductive material defining a substantially gas tight chamber having a bottom wall forming cups, a liquid cathode divided into a plurality of segregated electrically connected portions severally supported within said cups, a plurality of anodes depending into said chamber in insulated relation to the walls thereof and having arcing surfaces severally facing said cathode portions, a plurality of walls of electrically conductive material having the inner surfaces thereof invested with a coating of insulating material severally encompassing said anodes in electrically insulated relation thereto and forming, with the associated portions of said cathode and the top wall of said casing, a plurality of separate chambers within the first said chamber, means severally associated with said cathode portions for continuously vaporizing and for continuously ionizing material thereof to form a medium for the continual flow of current between the respective said anodes and the associated portions of said cathode, means for controlling the density of said vapor comprising means forming passages for the flow of a cooling fluid in heat transfer relation to said walls, and means for evacuating said chambers.

OTHMAR K. MARTI.

CERTIFICATE OF CORRECTION.

Patent N 2,262,189. November 11, 19m.

OTHHAR K. NARTI..-

It is hereby certified that error appears in the printed specification of the above nuinbered peteht r q r ng correction as follows: Page 5, sec-- 0nd column, line 52, claim 1, for "separated" read --separate--; line 1 8,

claim 2, for "manitaining" read "maintaining"; and that the said Letters- Patent should be read with this correction therein that the same may conform to .the'record of the casein the Patent Office.

Sig ed'and sealed this 25rd day of December, A. D. 19111.

Henry: Van Arsdale, (Seal) Acting Commissioner of Patents. 

